1. Field of the Invention
The invention relates to a device for liquid removal from a drilled hole equipped for gas production from an underground accumulation, under the conditions in which a downward liquid film flow on the tubing string wall occurs.
2. Description of the Related Art
There are known devices for removal of fluids from a drilled hole, in the conditions in which a two-phase flow occurs, equipped for natural gas production, consisting of upper short liner and lower long liner, so that it remains a free space between a lower flared end of the short liner and an upper end of the long liner, to the long liner there being secured, at the lower side, a cylindrical housing integral, in its turn being fixed, at the upper side, with a connection joint to the short liner, between the housing and the liners there remaining an annular space in which the liquid slips through the free space, to the long liner, in front of an orifice machined therein, there being secured either a siphoning pipe located inside the annular space or a non-balanced gas-lift valve.
The disadvantages of these devices consist in that they permit the removal of only a relatively low liquid volume, due to the low differential pressure; there also exhibits the possibility of failing to initiate the discharge of the fluid accumulated into the chamber when the differential pressure is very low, within few centimeters of water column.
Surprisingly, it has been found that by simultaneously creating a differential hydrostatic pressure between the upper liquid level in a liquid accumulation chamber, in which the liquid gathered from the downward flowing film, as a part of the total liquid quantity of the two-phase mixture flowing upward and the upper level of the liquid in a siphoning path with a configuration allowing the creation of a trapped gas volume, and between the upper and the lower liquid levels in the siphoning path, respectively, and at the same time, between the levels of a liquid column in a short-circuiting pipe with a configuration allowing the controlled removal of the active trapped gas volume which is in a hydrodynamic communication with the siphoning pipe, produces the pressure change of the trapped gas volume between the upper and lower liquid levels in the siphoning path, and the level of one of the free surfaces of the liquid column in the short-circuiting pipe, which creates the conditions for a controlled flow initiation from the accumulation chamber into the tubing string, leading to the accumulation chamber's discharge.
The trapped gas whose pressure and volume vary with the increase of the liquid level in the accumulation chamber, provides a controlled liquid removal from the accumulation chamber as long as the short-circuiting pipe has a relatively reduced remnant liquid volume, and the liquid column levels are inside of some spaces whose volumes exceed the remnant liquid volume by at least 50%.
The problem solved by the device claimed by the invention consists in the control of the liquid removal from an accumulation chamber inserted a gas flow tubing string, until it is completely discharged.